Blood oxygenator and pump apparatus



Sept. 7, 1965 G. FIELDS BLOOD OXYGENATOR AND PUMP APPARATUS 2 Sheets-Sheet 1 Filed May 1, 1961 INVENTOR. laws 6, 251.05

Sept. 7, 1965 G. FIELDS BLOOD OXYGENA'IOR AND PUMP APPARATUS 2 Sheets-Sheet 2 Filed May 1, 1961 INVENTOR. laws 6. [/5403 United States Patent aznaear BLUUD UXYGENATUR AND PUMP APPARATUS Louis G. Fields, 11662 Sunset Blvd, Los Angeles, Calif. Filed May 1, 1961, Ser. No. 106,690 24 (Ilaiins. (Cl. 128-214-) The present invention relates to extracorporeal circulation apparatus, and more particularly to apparatus capable of oxygenating venous blood, and of returning the oxygenated blood to the body of a human being or animal.

An object of the present invention is to provide an improved apparatus capable of operating in an efiicient and elfective manner in removing carbon dioxide from the blood and saturating it with oxygen.

Another object of the invention is to provide a blood oxygenator through which the venous blood will distribute in thin film form over a combined large surface,

providing a large area for contact of the blood by the oxygen in removing carbon dioxide therefrom.

A further object of the invention is to provide a blood oxygenator having an exchange bed comprising a plurality of relatively small pieces over which the blood can flow, the pieces being shaped to minimize contact therebetween, thereby reducing resistance to flow of the blood through the bed, insuring its distribution over the full cross-section of the bed, while at the same time permitting counterfiowing oxygen to remove carbon dioxide from the entire blood volume and replace and saturate the blood with oxygen.

An additional object of the invention is to provide an improved blood oxygenator capable of removing carbon dioxide from the blood and of replacing it with oxygen, and of also defoaniing and debubbling the oxygenated blood.

Yet another object of the invention is to provide a blood oxygenator having an exchange bed resting upon a support capable of filtering the blood, the oxygenated blood flowing through the filter being subjected to a relatively low pressure differential, such as that incident to gravity alone, to prevent crushing of the blood cells inpassing through the filter.

Still a further object of the invention is to provide a blood oxygenator through which the blood can flow smoothly in a direct line, and preferably by gravity, with a minimum of resistance.

Another object of the invention is to provide a blood oxygenator having a much greater volume for oxygenating the blood to the total blood volume of the system.

It is a further object of the invention to provide an apparatus for pumping blood that simulates the action of the heart. For example, the pump apparatus fills with blood by gravity and forces the blood upwardly to the patient.

Another object of the invention is to provide an apparatus capable of pumping blood to a patient, which is incapable of a pumping action to the patient upon interruption of the blood supply, thereby preventing the pumping of air or oxygen to the patients circulatory system. The pumping action cannot be eliected despite the continued operation of the apparatus.

Still another object of the invention is to provide an apparatus capable of pumping blood to a patient, which i will automatically cease operating upon interruption of 3,204,631 Patented Sept. 7, 1965 Yet a further object of the invention is to provide an apparatus for pumping blood to a patient, in which the blood cells are not crushed, the blood cells being subjeted only to the desired fluid pressure at which the blood is being supplied to the patient.

Another object of the invention is to provide an apparatus for pumping blood to a patient which requires only a source of oxygen under pressure for its operation, thereby avoiding the need for and reliance upon any other source or sources of power.

An additional object of the invention is to provide an apparatus for pumping blood which is reliable, compact, portable, and easily cleaned and maintained in proper operating condition.

A further object of the invention is to provide an apparatus for pumping blood in which the blood discharged by the apparatus to the patient can be maintained at any desired temperature.

Yet anothe object of the invention is to provide a blood oxygenator and pump, in which oxygen is used for operating the pump, the oxygen exhaust from the pump being supplied to the oxygenator, thereby effecting savings in the quantity of oxygen used in the system.

A further object of the invention is to provide a blood oxygenator and pump in which there is an in-line flow of blood in the oxygenator and pump, reducing resistance to blood flow and increasing the oxygenated blood voltune and pump volume in proportion to the total blood volume in the entire system.

Still a further object of the invention is to provide a. blood oxygenator and pump that can be readily disassembled from other portions of the apparatus, for disposal or cleaning and sterilizing.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of a form in which it may be embodied. This form is shown in' the drawings accompanying and forming part of the present specification. It will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

FIGURE 1 is a side elevational view of blood oxygenator and pump apparatus embodying the invention;

FIG. 2 is a vertical section, on an enlarged scale, taken along the line 2-2 on FIG. 1, with the pump in one operative position;

FIG. 3 is a view similar to FIG. 2 illustrating the control mechanism of the pump in somewhat diagrammatic form.

The apparatus illustrated in the drawings includes an upper blood oxygenerator 10 and a lower pump and fluid motor 11 for pumping the oxygenated blood to a patient. The blood oxygenerator includes a vertical cylinder 12, which is preferably made of a transparent material, such as a suitable transparent plastic, so that the interior of the cylinder is visible. The cylinder has a lower collector and settling reservoir 13, the wall 14 of which tapers in a downward and inward direction towards a central outlet passage 15. At the upper portion of the reservoir, a suitable support and filter screen 16 is provided, this screen being retained in place in any suitable manner. Resting upon this screen is a lower bed 1'7 of spheres or sponge, or both, which are made of a suitable plastic material for the purpose of deforming and debubbling the oxygenated blood flowing downwardly therebetween. As an example, the plastic spheres, which may be made of nylon or polypropylene resin, can be about one-half inch in diameter. Disposed in the cylinder 12 above the deforming and debubbling spheres and/ or sponge 17 is a mass or bed of blood oxygenating material 18, consisting of relatively small-shaped plastic pieces that will offer a minimum of contact with one another, allowing the blood to flow by gravity down between the plastic pieces and be distributed thereover in thin film foam, and also insuring the distribution of the blood across the entire area of the cylinder. The plastic pieces which may also be made of nylon or polypropylene, or other suitable material, may be of Berl saddleshape about a quarter of an inch in lateral dimension. Such pieces will not tend to stack directly upon one another, and will provide large void spaces therebetween through which blood can flow by gravity downwardly through the bed 18, oxygen and carbon dioxide removed from the blood flowing in an upward direction.

Venous blood derived from the patient will flow through a blood inlet line 19 into a perforated blood distributor or manifold 20 in the upper portion of the cylinder 12. The blood discharges from the manifold into the upper portion of the oxygenating bed 13, flowing by gravity downwardly therethrough. At the same time, oxygen from a suitable source can flow through an oxygen inlet line 21 in to a perforated manifold 22 extending across the lower portion of the cylinder below the support filter screen 116, the oxygen fiowing upwardly through the screen and through the deforming and debubbling bed 17, and continuing upwardly through the oxygenating bed 18, where the oxygen comes in contact with the blood disposed in thin film form on the plastic pieces, removing the carbon dioxide from the blood and replacing it with oxygen. The carbon dioxide and excess oxygen can exhaust through a suitable vent, opening or port 23 in the upper end wall 24 of the cylinder.

The oxygenated blood flows downwardly over the plastic spheres and/or sponges 1'7 where any entrapped gases, such as oxygen, will be released, the deformed and debubbled blood then passing through the support filter screen 16 into the collecting and settling reservoir 13 therebelow.

It is to be noted that the blood flows by gravity through the exchange bed 18, the plastic pieces effecting distribution of the blood as a thin film over the surfaces of each piece, for efiicient contact by the counterfiowing oxygen. The plastic pieces effect a distribution of the blood over a wide angle and area of the exchange bed, avoiding channeling of the blood or its concentration through a relatively small cross-sectional area of the bed. To facilitate the deforming action of the plastic spheres or sponge 17, they may, if desired, be coated with a silicone antifoam material. The blood fiowing through the filter screen 16 only has the hydrostatic head of the blood thereabove acting upon it. As a consequence, there is a comparatively low pressure differential acting on the blood and forcing it through the filter screen, which minimizes any harmful effects on the blood cells in producing their crushing or breakdown, and also tending to prevent any foreign substances that might be present from being forced through the filter screen. The arrangement disclosed has a minimum resistance to downward flow of the blood, since such fiow is in a direct line from the upper perforated blood distributor or mainfold 20 into the lower reservoir, the fiow resulting from the action of gravity alone. Changes in direction of the flow, and the like, are avoided so that the blood oxygenator has a comparatively great oxygenating volume to the total blood volume of the system.

The blood oxygenator cylinder or chamber 12; may be formed integrally with a blood pump housing 25 disposed directly below the cylinder and its reservoir 13. The blood from the reservoir may flow by gravity through the central axial passage 15, which is preferably elongate, into the upper end of the blood pump chamber or cylinder 27. A jacket space 26 is provided between the cylinder 27, the reservoir passage wall 28, reservoir 14 and outer housing 25 through which a suitable heat exchange medium can be caused to flow, for the purpose of either heating or cooling the oxygenated blood. For example, water at a desired temperature can fiow through an inlet line 29 into the jacket 26, the water flowing from the jacket through a suitable outlet line 30. The water flowing through the jacket will have a temperature corresponding to the desired temperaure of the blood to be pumped to the artery of the patent.

Disposed within the vertical pump cylinder 27 is a vertically arranged pump piston 31 having a flexible diaphragm 32 secured to its upper end face or surface. This flexible diaphragm has an inner skirt portion 33 extending downwardly around the periphery of the pump piston, which is free from attachment to the piston, this inner skirt portion being integral with an outer skirt portion 34 which is laterally spaced therefrom, and which has an outwardly directed flange 35 clamped between the lower end of the the cylinder housing 25 and the upper end of a pump or motor casing or housing 36, suitably secured to the cylinder housing 25. The flange 35 forms a gasket type of seal between the lower end of the cylinder housing and the upper end of the frame or housing 36. As the pump piston 31 reciprocates in the cylinder, the lengths of the inner and outer skirt portions 33, 34 of the diaphragm seal change, as is evident from a comparison between the positions shown in FIGS. 2 and 3, to prevent leakage downwardly between the piston and the cylinder. At all times, however, the inner and outer skirt layers 33, 34 are spaced substantially from one another, so that they do not frictionally engage each other. The annular space 37 between the inner and outer skirt layers is sufiicient for the reception of oxygenated blood, without imposing any mechanical pressure upon the blood.

As the pump piston 31 moves downwardly, the blood will flow by gravity through the inlet passage 15 and around a valve head 38 into the cylinder 27 This valve head is secured to a valve stem 39 extending upwardly through the central passage 15 and having a diameter substantially less than the diameter of the passage, so that the blood can flow downwardly therebetween. The upper end of the valve stem is secured to ahead 44) having a plurality of circumferentially spaced fingers 41 adapted to rest against the bottom 3.4 of the reservoir when the valve head 38 occupies a downward position from engagement with its companion valve seat 42 surrounding the passage 15. When the pump piston 31 moves downwardly, the valve head 38 moves downwardly away from its seat 42, the blood flowing from the reservoir 13 through the spaces between the fingers 41 into the passage 15, and down through the pasage and around the valve head 38 into the pump cylinder 27. If the pump cylinder is full of blood, upon cessation of the downward movement of the piston 31, the valve head 38 will float upwardly in the blood and engage its seat 42 to close the passage 15 against return flow of blood therethrough. Accordingly, upward movement of the pump piston 31 will force the blood in the cylinder out through a lower discharge port 43 through the cylinder wall, which is disposed a substantial distance below the inlet passage 15 and preferable adjacent to the flange 35 of the diaphragm seal. The blood fiows from the outlet passage or port into an outlet check Valve 4-4 suitably secured to the outer wall of the apparaus, this check valve having a valve seat 4-5 adapted to be engaged by a ball check valve element 46, when the latter is permitted to move downwardly into engagement with the seat. On its pumping stroke, the piston 31 will force the blood out through the valve seat 45, unseating the ball valve element 46, so that the blood is caused to flow around the latter and out of the check valve into a blood outlet or delivery hose 47 leading directly or indirectly to the artery of the patient. When the pump piston is no longer discharging blood into the check valve, the ball element 46 move downwardly into engagement with its companion seat 45, to prevent return flow of blood into the pump cylinder 27.

In the event that there is no blood in the pump chamber 27, or insufficient blood to fill the same, the blood inlet check valve element 38 will not move upwardly into engagement with its seat 42, since it only engages the seat as the result of floating upwardly in the blood in the chamber, because of its buoyancy. Consequently, if the cylinder 27 contains substantial air or oxygen, such that there is no or insufl'icient blood at the upper end of the cylinder, the movement of the pump piston 31 upwardly will not effect engagement of the valve head 38 with its companion seat 42, in order to close the inlet passage 15. Upward movement of the piston will, therefore, result in nothing more than the forcing of the air 'or oxygen back through the inlet passage into the reservoir 13. None of such air or oxygen will be forced through the discharge passage 43 and the outlet check valve 44 into the line or hose 47 leading to the patients artery. Accordingly, air, oxygen, or any other gas, cannot be pumped to the patients artery, regardless of continuing operation of the pump.

The pump is moved upwardly on its power stroke by a fluid motor 48, which is preferably operated by oxygen under pressure. The fluid motor includes a motor piston 49 having its upper portion 50 piloted in the lower portion of the pump piston 31, the two pistons being secured together for joint movement by a transverse coupling pin 51 extending outwardly through a longitudinal slot 52 in the pump and motor cylinder 36 and also outwardly through an aligned longitudinal slot 53 in the outer housing portion or frame 54 of the apparatus. The outer portion of the pin 51 is suitably secured to a vertical operating rod 55, to which suitable upper and lower valve actuating trip arms 56, 57 are secured. Such arms may be adjustably mounted relative to one another so as to vary the length of stroke of the pump and motor pistons 31, 49, and thereby vary the volume of blood delivered by the pump piston on each discharge stroke. The rod may have a suitable control knob 58 secured to it for manual shifting of the pistons 31, 49 and of the valve control mechanism whenever such actuation becomes desirable.

The lower end of the motor piston 49 is also secured to a suitable diaphragm seal 59 of flexible material. This seal may, if desired, be the same as the pump piston seal 32, which may be a Bellofram seal. The central base portion of the seal merges into an inner skirt portion 60, which, in turn, merges into an outer skirt portion 61 terminating in an outwardly directed flange 62 clamped between the lower end of the cylinder 36 and the upper end of a gas pressure cylinder or chamber 63, the cylinders being suitably secured together, as by means of a clamp band 64. When a suitable gas, such as oxygen under pressure, is allowed to flow through the cylinder line 65 into the lower portion of the pressure chamber 63, the motor piston 49 and the pump piston 31 are caused to rise, for the purpose of discharging the blood from the pump cylinder 27 toward the patient. When the cylinder line 65 is connected to an exhaust line, the pistons lower by gravity to draw an additional supply of blood from the reservoir 13 into the pump cylinder 27. However, as described hereinbelow, there is suflicient friction in the seal mechanisms 32, 59 of the pistons, and the other portions of the apparatus connected thereto, to prevent the pistons from dropping by gravity in the cylinders in the absence of a supplemental force imposed by the hydrostatic head of blood in the apparatus acting in a downward direction over the area of the pump piston 31. Accordingly, if the pump cylinder 27 does not contain blood, the pistons will not drop, the operation of the apparatus automatically ceasing, until the blood supply in the reservoir 13, the inlet passage 15, and the pump cylinder 27 is replenished.

The motive power for actuating the motor piston 49,

and, therefore, the pump piston 31 on a power stroke is preferably supplied by oxygen under pressure. As disclosed, oxygen under pressure from a suitable source flows through an inlet line 66 to a pressure or volume regulator 67. If the pressure supplied to the fluid motor cylinder and piston is to be maintained at a constant value, the pressure regulator 67 will be suitably adjusted, the oxygen from the regulator flowing through a suitable line 68 leading into a control valve 69 that determines the operation of the fluid motor. The oxygen flows into an inlet passage 76 in the valve and into a chamber 71. Above this chamber is a cylinder 72 containing a piston valve 73 having suitable side seal rings 74 at opposite ends thereof. adapted to seal against the side wall of the cylinder. One end of the valve cylinder communicates through a suitable exhaust line 75 with a pressure inlet trip valve 76 having a valve head 77 urged against its companion valve seat 78 by a spring 79. Extending from this valve head is a stem 80 adapted to be engaged by the upper trip arm 56 secured to the pistons 31, 49. Another exhaust line 81 leads from the opposite end of the valve cylinder to another pressure exhaust trip valve body 82, a spring '79 in this valve body urging a valve head 7 '7 into engagement with a companion seat 78 to close the valve. Extending from this valve head is another valve stem 80 adapted to be engaged by the lower arm 57, which is connected for movement with the pump and motor pistons 31, 49.

As disclosed in FIG. 3, oxygen under ressure enters the chamber 71 and can then flow into a radial passage 83 in the piston valve, and then in opposite directions therefrom through ports 84 into the cylinder at both sides of the piston valve 73. Opening of either trip valve 76, 82 will allow the oxygen in its companion end of the cylinder to exhaust to atmosphere, the oxygen pressure at the other end of the cylinder then appropriately moving the piston valve. Thus, as disclosed in FIG. 3, the pressure inlet trip valve 76 is soon to be shifted to an open position by the upper arm 56, whereupon pressure will predominate at the left end of the cylinder 72, forcing the piston valve '73 to the right (as shown in FIG. 3). As the piston valve moves to the right, it shifts a shuttle slide valve 85 with it to the right, and thereby places the line 65 leading to the motor cylinder 63 in communication with the pressure inlet line 68 through the interior of the shuttle valve, which will then be disposed over the cylinder inlet port 86 and the pressure inlet port 76. The spring 87 in the piston Valve urges the shuttle valve 85 downwardly to maintain it sealed against a companion surface of the valve body.

Oxygen under pressure will then enter the fluid motor 43 to elevate the pistons 49, 31. As soon as the pistons are elevated a slight distance, the arm 56 is moved away from the inlet trip valve stem 8%) and the valve 76 will close. However, the piston valve 73 will remain in its position at the right of the valve cylinder 72, since the pressure on both sides of the piston valve will then be balanced. The pistons 49, 31 move upwardly, the pump piston 31 being on its blood discharge stroke, until the lower trip arm 57 moves upwardly into engagement with its companion trip valve 82, shifting the latter to an open position, and placing the left end of the valve cylinder 72 in communication with the atmosphere. Fluid pressure is then relieved at the left end of the cylinder 72 and the oxygen pressure at the right end of the cylinder will then shift the piston valve 73 to the left, or to the position disclosed in FIG. 3, carrying the shuttle valve 85 also to the left and placing the cylinder line 65 in communication with an exhaust port 88 leading to an exhaust line 89. The pressure in the pump cylinder 63 is thereby relieved, the pump piston 31 and motor piston 49 then lowering in order to allow an additional volume of blood to gravitate past the inlet valve head 38 into the pump cylinder 27, until the upper trip arm 56 again engages the inlet trip valve 76 to repeat the foregoing cycle.

The oxygen from the oxygen inlet line 68 can also pass through another oxygen line 9d connected with the line 21 that discharges oxygen into the header 22 below the filter screen 16, to effect oxygenation of the blood flowing downwardly through the beds 18, 17. The volume of oxygen passing through the line 21 may be determined by suitably adjusting a needle valve 91, there being a suitable coupling 92 in the oxygen line 22 for the purpose of permitting disassembly of the apparatus, whenever desired. The exhaust line 89 can communicate with the atmosphere, but in the interest of saving oxygen, it can be connected to the oxygen pipe or line 21 leading to the blood oxygenator. Perferably, the exhausting oxygen will pass through a suitable filter 93 before being allowed to flow to the blood oxygenator.

The regulator 67 can be of a suitable form. Preferably, it is one which can either maintain the pressure of the oxygen supplied to the motor 48 constant, or it can be of the type that will insure a constant delivery of blood volume by the pump to the patient. As shown diagrammatically in FIG. 3, the regulator can perform selectively both of the aforenoted functions. Thus, the oxygen from a suitable line 66 can flow to an inlet port 100 in a valve body 1G1, shifting a valve head 102 downwardly against the force of a spring 163, and then flowing into the line ht) leading to the needle valve 91 and to the other line 65 leading to the control valve 69 of the fluid motor 48. The pressure in the line 68 leading to the control valve mechanism is allowed to enter a chamber 1114 having a diaphragm 1&5 extending thereacross. This diaphragm is urged in one direction by a helical compression spring 1416 acting through a suitable pin 1137 upon the valve head 1112 and tending to shift the latter to a more fully open position. The outer end of the spring engages a suitable spring seat 198 bearing against a threaded adjusting screw 109 threaded in the valve body 101. By suitably turning the screw 109, the tension of the spring 166 can be varied and the force that this spring imposes upon the valve head 102 and tending to shift it to open position.

counteracting the force of the spring 1% tending to shift the valve head 162 to an open position is the pressure in the valve outlet 110, which passes through a port 111 into the chamber 104 for action in the opposite direction on the diaphragm 105 and tending to overcome the force of the spring 106, at least to some extent. Thus, as the pressure actin on the diaphragm 105 decreases, the spring is capable of opening the valve 162 to a fuller extent so that the pressure in the valve outlet 110 is again increased. crease, then such pressure acts on the diaphragm 105 and offsets the spring force 106 to a greater extent, allowing the valve head 1112 to move to a more fully closed position, which then tends to recrease the pressure in the valve outlet 110. Accordingly, the pressure in the valve outlet is maintained at a substantially constant value.

By suitably adjusting the pressure control screw 109, the pressure in the motor cylinder 63 can be selected. This pressure preferably equals the desired bood pressure of the patient. Since the effective cross-sectional area of the motor piston 49 and the pump piston 31 are preferably equal, the oxygen pressure at the outlet 1111 of the regulator valve 67 will equal the desired pressure imposed on the blood for delivery to the patents circulatory system. Accordingly, by appropriate observation on a pressure gauge 112 connected to the outlet line 68 leading from the pressure regulator, one can adjust the oxygen pressure and thereby adjust the pressure at which the blood will be delivered to the patient.

In lieu of maintaining a constant blood pressure, it may be desired to deliver blood at a constant rate to the patient. If the corporeal resistance of the patient were to increase, the rate of flow of blood delivered to the patient would decrease, in the event that the pressure regulator 67 were to maintain a constant gas pressure. As dis- If the pressure in the valve outlet tends to inclosed in FIG. 3, a regulator can be provided to insure the supply of a constant fiow of blood to the patient. As shown, the outlet line 68 leading from the regulator has an orifice 1'13 therein to provide a pressure drop. A line 1 14- leads from the downstream side of the orifice to a. valve .115 which can be adjusted to place the line on the downstream side of the orifice in communication with a regulator valve "chamber 116 on the side of the diaphragm containing the spring 106. With the regulator arrangement disclosed, any increase in corporeal resistance of the patient would provide .an increase in the pressure on the downstream side 68 of the orifice. Such increase in pressure would be directed into the spring chamber -116 to provide a force on the diaphragm supplementing the force of the spring 1%, thereby urging the valve head 162 to a more fully open position, permitting a greater supply of oxygen to flow through the orifice 113, and thereby resulting in delivery of blood at a greater pressure to the patient. On the other hand, should the conporeal resistance decrease, the pressure on the downstream side 68 of the orifice 1 13 would also correspondingly decrease, thereby decreasing the pressure force on the diaphragm assisting the force of the spring 1%; whereupon the valve 102 would shift in a how restricting direction, reducing the volume and pressure of oxygen flowing through the orifice 1'13, and thereby correspondingly reducing the pressure of oxygen in the fiuid motor pressure chamber 63 and the pressure at which the blood is delivered by the pump to the patient, thereby maintaining the blood flow at a constant volume.

The regulator disclosed in FIG. 3 can be changed selectively between a pressure regulator and a constant flow regulator by manipulating the two way valve 115. The two-way valve can be turned so that the line 117 leading to the spring chamber 116 is placed in communication with the atmosphere, in which event the regulator will maintain a constant pressure in the outlet line 68. By turning the two-way valve 115 to a position placing the spring chamber 116 out of communication with the atmosphere and in communication with the line 1 14 leading to the downstream side of the orifice 1 13, the regulator is changed to one that maintains the flow of oxygen constant, and thereby maintains the delivery of blood to the patient substantially constant.

As mentioned above, the pump on its upward or pumping stroke is incapable of delivering blood to the patient in the event of the pump chamber 27 being fully or partially devoid of blood, since the valve head 38 will not float upwardly in the blood to a closed position. If sufficient quantity of blood is not present in the pump cylinder 27 and also in the passage 15 thereabove, the pump piston 31 Will not move downwardly from its upward position. The weight of the pump piston and the parts connected thereto is insufficient to overcome the frictional resistance to downward movement offered by the several parts of the apparatus. A sufficient column or height of blood must be present above the pump piston 31, acting downwardly over its cross-sectional area, for the purpose of shifting the pump piston downwardly to a position in which it can then be moved upwardly for the purpose of delivering blood to the patient. Preferably, the pump and motor pistons 31, 49 are made very light, and can be hollow to decrease their weight.

Because of the use of the diaphragm type of seal 32 on the pump piston, and particularly the Bellofrarn seal, the blood cells are not pressed between any contacting surfaces, as the result of reciprocation of the pump piston 3-1 in the cylinder. If the piston were caused to slide along a cylinder, some of the blood cells would be mechanically pressed therebetween and thereby crushed. The blood cells are subjected only to the fluid pressure imposed upon them by the piston 31, and not to any mechanical crushing or compressive forces. It is to be noted that the inner and outer folds or skirt portions 33, 34 of the Bellofram seal are always spaced from one another, so that in moving relative to one another they do not effect any mechanical compression on the blood cells, as would produce their crushing. About the only part that could effect a crushing action is the ball check valve 46, when it moves downwardly into contact with its seat. However, the quantity of blood that might be adversely aflected in this manner is insignificant compared to the entire blood volume passing through the check valve 44.

It is to be noted that there is an in-line flow of blood through the blood oxygenator llil and into the pump 11. Again, it is pointed out that such in-line flow conserves volume and space, there being a maximum blood oxygenati-ng and pump volume in comparison to the volume of the overall system. The additional volume of the system is substantially only that of the volume of the blood inlet 10 from a vein and the outlet mechanism 47 leading directly or indirectly to the artery of the patient. The pump simulates the action of the heart, inasmuch as it fills with blood gravitationally, forcing the blood upwardly through the discharge line 4'7 to the artery, the blood passing to the latter either directly or indirectly, as desired. The pump requires only the same sources of oxygen under pressure for its operation that is needed in effecting oxygenation of the blood. As a result, it is not dependent upon other sources of power which might fail, such as, for example, electric power. Moreover, the apparatus is compact, occupies a minimum of space, since the effective volume in oxygenating and pumping the blood is large compared to the overall blood volume of the system. Its in-line flow makes its maintenance relatively easy, as well as its cleaning and sterilizing.

If desired, the blood oXygenato-r and the pump can be easily disassembled from the fluid motor, as, for example, by merely releasing a clamp band 120 securing the cylinder 27 to the cylinder 36 and frame 54, which will permit the oxygenator and blood pump to be disposed of, or, if desired, cleaned and sterilized; whereupon the same or a replacement blood oxygenator and pump can be assembled to the fluid motor for operation. In connection with disassembly of the apparatus, the pin 51 can be pulled laterally outwardly to disconnect the pump piston 31 from the motor piston 49, allowing the Bellofram seal 32 and the pump piston 31 to be replaced.

I claim:

1. In apparatus for supplying blood to a patient: a container for blood; a pump chamber having an upper blood inlet communicating with a lower portion of said container and a lower outlet; piston means movable in said chamber for forcing blood therein into said outlet; a valve device buoyant in blood movable upwardly by blood in said chamber to closed position across said inlet; and means retaining said valve device adjacent to said inlet when said valve device is in open position.

2. In apparatus for supplying blood to a patient: a container for blood; a cylinder below said container and having an upper blood inlet communicating with a lower portion of said container and a lower outlet substantially below said inlet; a valve device in said cylinder buoyant in blood and movable upwardly by blood in said cylinder to closed position across said inlet; means limiting downward movement of said valve device to a short distance when in open position; and a piston in said cylinder movable upwardly therein to force blood from said cylinder into said outlet when said valve device is in closed position.

3. In apparatus for supplying blood to a patient: a con tainer for blood; a cylinder having an upper blood inlet communicating with a lower portion of said container and a lower outlet substantially below said inlet; a valve device in said cylinder buoyant in blood and movable upwardly by blood in said cylinder to closed position across said inlet; means retaining said valve device adjacent to said inlet when said valve device is in open position; a piston in said cylinder movable upwardly therein to force blood from said chamber into said outlet when said valve device is in closed position; said piston being spaced laterally from the side wall of said cylinder; and a diaphragm seal secured to said cylinder and piston and including an inner sleeve portion surrounding said piston, and an outer sleeve portion integral with said inner portion and attached to said cylinder and spaced laterally outwardly from said inner sleeve portion.

4. In apparatus for supplying blood to a patient: a container for blood; a cylinder having an upper blood inlet communicating with a lower portion of said container and a lower outlet substantially below said inlet; a valve device in said cylinder buoyant in blood and movable upwardly by blood in said cylinder to closed position across said inlet; means limiting downward movement of said valve device to a short distance when in open position; a piston in said cylinder movable upwardly therein to force blood from said chamber into said outlet when said valve device is in closed position; and a fluid motor connected to said piston for moving said piston in said cylinder.

5. In apparatus for supplying blood to a patient: a container for blood; a cylinder having an upper blood inlet communicating with a lower portion of said container and a lower outlet substantially below said inlet; a valve device in said cylinder buoyant in blood and movable upwardly by blood in said cylinder to closed position across said inlet; means retaining said valve device adjacent to said inlet when said valve device is in open position; a piston in said cylinder movable upwardly therein to force blood from said chamber into said outlet when said valve device is in closed position; a fluid motor connected to said piston for moving said piston in said cylinder; and means responsive to movement of said piston in said cylinder for controlling the operation of said fluid motor.

6. In apparatus for supplying blood to a patient: a container for blood; a cylinder below said container and having an upper blood inlet communicating with a lower portion of said container and a lower outlet substantially below said inlet; a valve device in said cylinder buoyant in blood and movable upwardly by blood in said cylinder to closed position across said inlet; means limiting downward movement of said valve device to a short distance when in open position; piston in said cylinder movable upwardly therein to force blood from said chamber into said outlet when said valve device is in closed position; a fluid motor having a piston connected to said pump piston for moving said pump piston in said cylinder; and means for supplying a motivating fluid to said motor for actuation of said motor and pump pistons.

7. In apparatus for supplying blood to a patient: a container for blood; a cylinder below said container and having an upper blood inlet communicating with a lower portion of said container and a lower outlet substantially below said inlet; a valve device in said cylinder buoyant in blood and movable upwardly by blood in said cylinder to closed position across said inlet; means retaining said valve device adjacent to said inlet when said valve device is in open position; a piston in said cylinder movable upwardly therein to force blood from said chamber into said outlet when said valve device is in closed position; a fluid motor having a piston connected to said pump piston for moving said pump piston in said cylinder; means for supplying a motivating fluid to said motor for actuation of said motor and pump pistons; and means responsive to movement of said pistons for controlling the supply and exhaust of said motivating fluid to said motor to effect reciprocation of said pistons.

8. In apparatus for supplying blood to a patient: a container for blood; a cylinder below said container and having an upper blood inlet communicating with a lower portion of said container and a lower outlet substantially below said inlet; a valve device in said cylinder buoyant in blood and movable upwardly by blood in said cylinder to closed position across said inlet; means retaining said valve device adjacent to said inlet when said valve device is in open position; a piston in said cylinder movable upwardly therein to force blood from said chamber into said outlet when said valve device is in closed position; a fiuid motor having a piston connected to said pump piston for moving said pump piston in said cylinder; and means for supplying a motivating fluid to said motor for actuation of said motor and pump pistons; the pressure actuatable areas of said pistons being substantially equal, whereby the pressure imparted to the blood by said pump piston substantially equals the pressure of the motivating fluid supplied to said motor.

9. In a pump for supplying blood to a patient: a cylinder having an upper blood inlet and a lower outlet substantially below said inlet; a valve device in said cylinder buoyant in blood and movable upwardly by blood in said cylinder to closed position across said inlet; vertical- 1y movable piston means in said cylinder movable upwardly therein to force blood from said cylinder into said outlet when said valve device is in closed position; a fluid motor having vertically movable piston means connected to said pump piston means for moving said pump piston means upwardly in said cylinder; said pump piston means and motor piston means being so proportioned and arranged as to have insuflicient weight to move downwardly of said cylinder alone, the hydrostatic head of fluid above said pump piston means supplementing the weight of both piston means to shift them downwardly of said cylinder.

lltl. In apparatus for supplying blood to a patient: an upper reservoir for blood; a cylinder below said reservoir having a lower outlet and an upper inlet substantially above said outlet comunicating with a lower portion of said reservoir; a valve device in said cylinder buoyant in blood and movable upwardly by blood in said cylinder to closed position across said inlet; vertically movable piston means in said cylinder movable upwardly therein to force blood from said cylinder into said outlet when said valve device is in closed position; means for moving said piston means upwardly in said cylinder; said piston means and moving means being so proportioned and arranged as to have insufficient weight to move downwardly of said cylinder alone, the hydrostatic head of blood in said cylinder and reservoir above said piston means supplementing the weight of said piston means and moving means to shift them downwardly of said cylinder.

11. In a pump for supplying blood to a patient: a cylinder having an upper blood inlet and a lower outlet substantially below said inlet; a valve device in said cylinder buoyant in blood and movable upwardly by blood in said cylinder to closed position across said inlet; vertically movable piston means in said cylinder movable upwardly therein to force blood from said cylinder into said outlet when said valve device is in closed position; means for moving said piston means upwardly in said cylinder; said piston means and moving means being so proportioned and arranged as to have insufiicient weight to move downwardly of said cylinder alone, the hydrostatic head of fluid above said piston means supplement ing the weight of said piston means and moving means to shift them downwardly of said cylinder.

12. In blood oxygenating and pump apparatus: a container having an upper inlet for venous blood, and a lower reservoir; a cylinder below said reservoir having a lower outlet and an upper inlet communicating with a lower portion of said reservoir; an exchange bed in said container above said reservoir comprising a mass of small pieces over and between which the blood can flow from said inlet to said reservoir; means for supplying oxygen in said container at an upper region of said reservoir below said bed for upward passage through said bed to oxygenate the blood therein; a valve device in said cylinder buoyant in blood and movable upwardly by blood in said cylinder to closed position across said inlet when said cylinder is completely filled with blood; and a piston in said cylinder movable upwardly therein to force blood i2 from said cylinder into said outlet when said valve device is in closed position.

13. In blood oxygenating and pump apparatus: a container having an upper inlet for venous blood, and a lower reservoir; a pump chamber below said reservoir having a lower outlet and an upper inlet substantially above said outlet communicating with the lower portion of said reservoir; piston means movable upwardly in said chamber for forcing blood therein into said outlet; a valve device buoyant in blood movable upwardly by blood in said chamber to closed position across said chamber inlet when said chamber is completely filled with blood; and means retaining said valve device adjacent to said inlet when said valve device is in open position.

14. In blood oxygenating and pump apparatus: a container having an upper inlet for venous blood, and a lower reservoir; a cylinder below said reservoir having a lower outlet and an upper inlet communicating with a lower portion of said reservoir; an exchange bed in said container above said reservoir comprising a mass of small pieces over and between which the blood can flow from said inlet to said reservoir; means for supplying oxygen in said container at an upper region of said reservoir below said bed for upward passage through said bed to oxygenate the blood therein; a valve device in said cylinder buoyant in blood and movable upwardly by blood in said cylinder to closed position across said inlet when said cylinder is completely filled with blood; a piston in said cylinder movable upwardly therein to force blood from said cylinder into said outlet when said valve device is in closed position; said piston being spaced laterally from the side wall of said cylinder; and a diaphragm seal secured to said cylinder and piston and including an inner sleeve portion surrounding said piston and an outer sleeve portion integral with said inner portion and attached to said cylinder and spaced laterally outwardly from said inner sleeve portion.

15. In blood oxygenating and pump apparatus: container having an upper inlet for venous blood, and a lower reservoir; an exchange bed in said container above said reservoir through which blood can flow from said inlet to said reservoir, a pump cylinder below said reservoir having a lower outlet and an upper inlet communicating with the lower portion of said reservoir; a pump piston in said cylinder for forcing blood therein into said outlet; a valve device buoyant in blood movable upwardly by blood in said cylinder to closed position across said inlet to said cylinder when said cylinder is completely filled with blood; a fiuid motor having a piston connected to said pump piston for moving said pump piston in said cylinder; means for supplying oxygen under pressure to said motor for actuation of said motor and pump pistons; means responsive to movement of said pistons for controlling the supply and exhaust of oxygen to said motor to effect reciprocation of said pistons; and means for conducting the exhaust oxygen from said motor to said container for upward passage through said bed.

16. In blood oxygenating and pump apparatus: a container having an upper inlet for venous blood, and a lower reservoir; an exchange bed in said container above said reservoir comprising a mass of small pieces over and between which the blood can fiow from said inlet to said reservoir; means for supplying oxygen in said container at an upper region of said reservoir below said bed for upward passage through said bed to oxygenate the blood therein; a cylinder below said reservoir having a lower outlet and an upper inlet communicating with a lower portion of said reservoir; a valve device in said cylinder buoyant in blood and movable upwardly by blood in said cylinder to closed position across said cylinder inlet when said cylinder is completely filled with blood; vertically movable piston means in said cylinder movable upwardly therein to force blood from said cylinder into said outlet when said valve device is in closed position; means for moving said piston means upwardly in said cylinder; said piston means and moving means being so proportioned and arranged as to have insuflicient weight to move downwardly of said cylinder alone, the hydrostatic head of fluid in said cylinder and reservoir above said piston means supplementing the weight of said piston means and moving means to shift them downwardly of said cylinder.

17. In blood oxygenating and pump apparatus: a container having an upper inlet for venous blood, and a lower reservoir; an exchange bed in said container above said reservoir comprising a mass of small pieces over and between which the blood can flow from said inlet to said reservoir; means for supplying oxygen in said container at an upper region of said reservoir below said bed for upward passage through said bed to oxygenate the blood therein; a cylinder below said reservoir having a lower outlet and an upper inlet communicating with a lower portion of said reservoir; a valve device in said cylinder buoyant in blood and movable upwardly by blood in said cylinder to closed position across said cylinder inlet when said cylinder is completely filled with blood; vertically movable piston means in said cylinder movable upwardly therein to force blood from said cylinder into said outlet when said valve device is in closed position; means for moving said piston means upwardly in said cylinder; said piston means and moving means being so proportioned and arranged as to have insufiicient weight to move downwardly of said cylinder alone, the hydrostatic head of fluid in said cylinder and reservoir above said piston means supplementing the weight of said piston means and moving means to shift them downwardly of said cylinder; and means for supplying a fluid medium around said cylinder and reservoir to effect heat exchange between the blood therein and said fluid medium.

18. In apparatus for supplying blood to a patient: a container for blood; a pump chamber having an upper blood inlet communicating with a lower portion of said container and a lower outlet; piston means movable in said chamber for forcing blood therein into said outlet; a valve device buoyant in blood movable upwardly by blood in said chamber to closed position across said inlet, said valve device including a stem extending int-o said inlet, and limit means on said stem for limiting downward movement of said valve device from said inlet to a short distance when in open position.

19. In blood oxygenating and pump apparatus: a container having an upper inlet for venous blood, and a lower reservoir; a cylinder below said reservoir having a lower outlet and an upper inlet communicating with a lower portion of said reservoir; an exchange bed in said container above said reservoir comprising a mass of small pieces over and between which the blood can flow from said inlet to said reservoir; means for supplying oxygen in said container at an upper region of said reservoir below said bed for upward passage through said bed to oxygenate the blood therein; a valve device in said cylinder buoyant in blood and movable upwardly by blood in said cylinder to closed position across said inlet when said cylinder is completely filled with blood; and means in said cylinder movable upwardly therein to force blood from said cylinder into said outlet when said valve device is in closed position.

20. In blood oxygenating and pump apparatus: a container having an upper inlet for venous blood, and a lower reservoir; an exchange bed in said container above said reservoir through which blood can flow from said inlet to said reservoir; a pump chamber below said reservoir having a lower outlet and an upper inlet communicating with the lower portion of said reservoir; pump means in said chamber for forcing blood therein into said outlet; a valve device buoyant in blood movable upwardly by blood in said chamber to closed position across said inlet to said chamber when said chamber is completely filled with blood; a fluid motor connected to said pump means for moving said pump means in said I4 chamber; means for supplying oxygen under pressure to said motor to actuate the same; and means for conducting the exhaust oxygen from said motor to said container for upward passage through said bed.

21. In blood oxygenating and pump apparatus: a container having an upper inlet for venous blood, and a lower reservoir; and exchange bed in said container above said reservoir through which blood can flow from said inlet to said reservoir; a pump chamber below said reservoir having a lower outlet and an upper inlet communicating with the lower portion of said reservoir; pump means in said chamber for forcing blood therein into said outlet; a valve device buoyant in blood movable upwardly by blood in said chamber to closed position across said inlet to said chamber when said chamber is completely filled with blood; a fluid motor connected to said pump means for moving said pump means in said chamber; means for supplying oxygen under pressure to said motor to actuate the same; means responsive to movement of said fluid motor for controlling the supply and exhaust of oxygen to and from said motor to effect its actuation; and means for conducting the exhaust oxygen from said motor to said container for upward passage through said bed.

22. In apparatus for receiving blood from and supplying it to a patient: a reservoir adapted to contain the blood; a cylinder below said reservoir and having an upper passage communicating with a lower portion of said reservoir and through which blood can flow from said reservoir into said cylinder, said cylinder having outlet means; vertically movable piston means in said cylinder below said passage; means for moving said piston means upwardly in said cylinder to discharge blood from said cylinder; said piston means being so proportioned and arranged as to have insuflicient weight to move downwardly alone, the hydrostatic head of blood in said cylinder through said outlet means and passage above said piston means supplementing the weight of said piston means to shift said piston means downwardly in said cylinder, reservoir; and means responsive to movement of said piston means in said cylinder for controlling operation of said moving means.

23. In apparatus for supplying blood to a patient: a reservoir adapted to contain the blood; a pump cylinder below said reservoir having a lower outlet and an upper inlet communicating with a lower portion of said reservoir; a valve device in said cylinder buoyant in blood and movable upwardly by blood in said cylinder to closed position across said inlet; means limiting downward movement of said valve device to a short distance from said inlet when in open position; piston means in said cylinder movable upwardly therein to force blood from said cylinder into said outlet when said valve device is in closed position; means for moving said piston means upwardly in said cylinder to discharge blood from said cylinder into said outlet; said piston means being so proportioned and arranged as to have insufficient weight to move downwardly alone, the hydrostatic head of blood in said cylinder and reservoir above said piston means supplementing the weight of said piston means to shift said piston means downwardly in said cylinder; and means responsive to movement of said piston means in said cylinder for controlling actuation of said moving means.

24. In apparatus for supplying blood to a patient: a container for blood; a pump chamber having an upper blood inlet communicating with a lower portion of said container and a lower outlet; piston means movable in said chamber for forcing blood therein into said outlet; a valve device buoyant in blood movable upwardly by blood in said chamber to closed position across said inlet, said valve device including .a head adapted to seat against said chamber to close said inlet and a valve stem extending through said inlet to the upstream side thereof; and means operatively associated with said stem on the upstream side of said inlet for retaining said head adjacent to said inlet when said head is in open position.

References Cited by the Examiner UNITED STATES PATENTS Witter 222334 Brauer 137-433 Desmet 128-214 Miner 103-50 X Conklin 222-383 X Gray 10337 Ragland 103-150 Schinnerer 103-50 X Calvin 1282l4 Burke 128-214 Everett 128-214 165 3,039,399 6/62 Everett 103-450 3,052,238 9/62 Broman et a1. 128214 FOREIGN PATENTS 1,108,782 9/55 France.

OTHER REFERENCES RICHARD A. GAUDET, Primary Examiner.

RICHARD J. HOFFMAN, Examiner. 

1. IN APPARATUS FOR SUPPLYING BLOOD TO A PATIENT: A CONTAINER FOR BLOOD; A PUMP CHAMBER HAVING AN UPPER BLOOD INLET COMMUNICATING WITH A LOWER PORTION OF SAID CONTAINER AND A LOWER OUTLET; PISTON MEANS MOVABLE IN SAID CHAMBER AND FORCING BLOOD THEREIN INTO SAID OUTLET; A VALVE DEVICE BUOYANT IN BLOOD MOVABLE UPWARDLY BY BLOOD IN SAID CHAMBER TO CLOSED POSITION ACROSS SAID INLET; AND MEANS RETAINING SAID VALVE DEVICE ADJACENT TO SAID INLET WHEN SAID VALVE DEVICE IS IN OPEN POSITION. 